vtkStripper not joining contiguous lines to form a single vtkPolyLine.

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1

Here is the rendering of three vtkLines:

image
image567×544 13 KB

Now I use vtkStripper in the hopes of getting a single vtkPolyLine:

    vtkSmartPointer<vtkPolyData> poly = vtkSmartPointer<vtkPolyData>::New();
    poly->SetPoints( points );
    poly->SetLines( segments );
    poly->GetCellData()->SetScalars( dataIndexes );


    vtkSmartPointer<vtkStripper> stripper = vtkSmartPointer<vtkStripper>::New();
    stripper->SetInputData( poly );
    stripper->SetMaximumLength( 200 );
    stripper->JoinContiguousSegmentsOn();
    stripper->Update();

    Application::instance()->logInfo("=====>" + QString::number( poly->GetNumberOfCells() ));
    Application::instance()->logInfo("=====>" + QString::number( stripper->GetOutput()->GetNumberOfCells() ));

Here’s what I get:
image

I was supposed to get just one object count in the second call.

Here is the data used to build the geometry:

test
8
x_initial
x_final
y_initial
y_final
z_initial
z_final
color_code
0.0	0.0	0.0	0.0	0.0	1.0	1
0.0	0.0	0.0	0.0	1.0	2.0	2
0.0	0.0	0.0	0.0	2.0	3.0	1

As can be seen, there is no geometry mismatch that would cause vtkStripper to misbehave.

I’ll appreciate any help.

2

Hello,

Could you try to run vtkCleanPolyData filter on the polydata before vtkStripper?

3

Yes, that solved it. Thanks a lotKenichiro! :grinning:

4

The code with the solution:

    vtkSmartPointer<vtkPolyData> poly = vtkSmartPointer<vtkPolyData>::New();
    poly->SetPoints( points );
    poly->SetLines( segments );
    poly->GetCellData()->SetScalars( dataIndexes );

    vtkSmartPointer<vtkCleanPolyData> cleanPolyData =  vtkSmartPointer<vtkCleanPolyData>::New();
    cleanPolyData->SetInputData( poly );
    cleanPolyData->Update();

    vtkSmartPointer<vtkStripper> stripper = vtkSmartPointer<vtkStripper>::New();
    stripper->SetInputConnection( cleanPolyData->GetOutputPort() );
    stripper->SetMaximumLength( 200 );
    stripper->JoinContiguousSegmentsOn();
    stripper->Update();

    Application::instance()->logInfo("=====>" + QString::number( poly->GetNumberOfCells() ));
    Application::instance()->logInfo("=====>" + QString::number( stripper->GetOutput()->GetNumberOfCells() ));
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